Where can more information be found about Bluetooth SCO audio support for a gumstix?
The new hardware supports SCO-over-HCI, and also provides a datapath for PCM data to pass directly from the bluetooth module to the CPU not encapsulated in HCI packets. The datasheet says that 3 simultaneous SCO connections are supported in hardware. Linux can support simultaneous SCO connections since the adapter is connected to the CPU on a UART. On the software side, there are two things which are needed yet to make this completely seemless, both of which are in hand: 1. Change the baud rate at which the bluetooth module connects to the gumstix UART so that HCI comms happens at 921600 baud instead of 115200 — this is needed for SCO over HCI. 2. Alternatively/additionally, implement a kernel audio driver which receives the PCM data from the bluetooth module with the NSSP on the gumstix host processor, and passes that PCM data to userspace. This method will work even with the baud rate at 115200, since the audio data is not passed over HCI. Also, check out Brad Midgley’s website here.
